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Driller T, Robinson JA, Clearwater M, Holland DJ, van den Berg A, Watson M. Quantitative examination of the anatomy of the juvenile sugar maple xylem. PLoS One 2023; 18:e0292526. [PMID: 37819934 PMCID: PMC10566711 DOI: 10.1371/journal.pone.0292526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 09/22/2023] [Indexed: 10/13/2023] Open
Abstract
New methodologies have enabled viable sap yields from juvenile sugar maple trees. To further improve yields, a better understanding of sap exudation is required. To achieve this, the anatomy of the xylem must first be fully characterised. We examine juvenile maple saplings using light optical microscopy (LOM) and scanning electron microscopy (SEM), looking at sections cut along differing orientations as well as macerations. From this we measure various cell parameters. We find diameter and length of vessel elements to be 28 ± 8 μm and 200 ± 50 μm, for fibre cells 8 ± 3 μm and 400 ± 100 μm, and for ray parenchyma cells 8 ± 2 μm and 50 ± 20 μm. We also examine pitting present on different cell types. On vessel elements we observe elliptical bordered pits connecting to other vessel elements (with major axis of 2.1 ± 0.7 μm and minor 1.3 ± 0.3 μm) and pits connecting to ray parenchyma (with major axis of 4 ± 2 μm and minor 2.0 ± 0.7 μm). We observe two distinct pit sizes on fibres with circular pits 0.7 ± 0.2 μm in diameter and ellipsoidal pits 1.6 ± 0.4 μm by 1.0 ± 0.3 μm. We do not observe distinct pitting patterns on different fibre types. The various cell and pit measurements obtained generally agree with the limited data available for mature trees, with the exception of vessel element and fibre length, both of which were significantly smaller than reported values.
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Affiliation(s)
- Tenaya Driller
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - James A. Robinson
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Mike Clearwater
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Daniel J. Holland
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Abby van den Berg
- Proctor Maple Research Center, University of Vermont, Underhill, Vermont, United States of America
| | - Matthew Watson
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
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2
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Fernández-de-Uña L, Martínez-Vilalta J, Poyatos R, Mencuccini M, McDowell NG. The role of height-driven constraints and compensations on tree vulnerability to drought. New Phytol 2023; 239:2083-2098. [PMID: 37485545 DOI: 10.1111/nph.19130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/07/2023] [Indexed: 07/25/2023]
Abstract
Frequent observations of higher mortality in larger trees than in smaller ones during droughts have sparked an increasing interest in size-dependent drought-induced mortality. However, the underlying physiological mechanisms are not well understood, with height-associated hydraulic constraints often being implied as the potential mechanism driving increased drought vulnerability. We performed a quantitative synthesis on how key traits that drive plant water and carbon economy change with tree height within species and assessed the implications that the different constraints and compensations may have on the interacting mechanisms (hydraulic failure, carbon starvation and/or biotic-agent attacks) affecting tree vulnerability to drought. While xylem tension increases with tree height, taller trees present a range of structural and functional adjustments, including more efficient water use and transport and greater water uptake and storage capacity, that mitigate the path-length-associated drop in water potential. These adaptations allow taller trees to withstand episodic water stress. Conclusive evidence for height-dependent increased vulnerability to hydraulic failure and carbon starvation, and their coupling to defence mechanisms and pest and pathogen dynamics, is still lacking. Further research is needed, particularly at the intraspecific level, to ascertain the specific conditions and thresholds above which height hinders tree survival under drought.
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Affiliation(s)
- Laura Fernández-de-Uña
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Rafael Poyatos
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- ICREA, Barcelona, 08010, Spain
| | - Nate G McDowell
- Pacific Northwest National Laboratory, Richland, WA, 99354, USA
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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Ren M, Dong L, Wang X, Li Y, Zhao Y, Cui B, Yang G, Li W, Yuan X, Zhou T, Xu P, Wang X, Di J, Li Q. Dual-Ion Co-Regulation System Enabling High-Performance Electrochemical Artificial Yarn Muscles with Energy-Free Catch States. Nanomicro Lett 2023; 15:162. [PMID: 37386318 PMCID: PMC10310689 DOI: 10.1007/s40820-023-01133-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/22/2023] [Indexed: 07/01/2023]
Abstract
Artificial yarn muscles show great potential in applications requiring low-energy consumption while maintaining high performance. However, conventional designs have been limited by weak ion-yarn muscle interactions and inefficient "rocking-chair" ion migration. To address these limitations, we present an electrochemical artificial yarn muscle design driven by a dual-ion co-regulation system. By utilizing two reaction channels, this system shortens ion migration pathways, leading to faster and more efficient actuation. During the charging/discharging process, [Formula: see text] ions react with carbon nanotube yarn, while Li+ ions react with an Al foil. The intercalation reaction between [Formula: see text] and collapsed carbon nanotubes allows the yarn muscle to achieve an energy-free high-tension catch state. The dual-ion coordinated yarn muscles exhibit superior contractile stroke, maximum contractile rate, and maximum power densities, exceeding those of "rocking-chair" type ion migration yarn muscles. The dual-ion co-regulation system enhances the ion migration rate during actuation, resulting in improved performance. Moreover, the yarn muscles can withstand high levels of isometric stress, displaying a stress of 61 times that of skeletal muscles and 8 times that of "rocking-chair" type yarn muscles at higher frequencies. This technology holds significant potential for various applications, including prosthetics and robotics.
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Affiliation(s)
- Ming Ren
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Lizhong Dong
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Xiaobo Wang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Yuxin Li
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Yueran Zhao
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
| | - Bo Cui
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Guang Yang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China
| | - Wei Li
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
| | - Xiaojie Yuan
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
| | - Tao Zhou
- Division of Nanomaterials and Jiangxi Key Lab of Carbonene Materials, Jiangxi Institute of Nanotechnology, Nanchang, 330200, People's Republic of China
| | - Panpan Xu
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
| | - Xiaona Wang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China
| | - Jiangtao Di
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China.
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China.
- Division of Nanomaterials and Jiangxi Key Lab of Carbonene Materials, Jiangxi Institute of Nanotechnology, Nanchang, 330200, People's Republic of China.
| | - Qingwen Li
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, People's Republic of China.
- School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, People's Republic of China.
- Division of Nanomaterials and Jiangxi Key Lab of Carbonene Materials, Jiangxi Institute of Nanotechnology, Nanchang, 330200, People's Republic of China.
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Miehe W, Czempik L, Klebl F, Lohaus G. Sugar concentrations and expression of SUTs suggest active phloem loading in tall trees of Fagus sylvatica and Quercus robur. Tree Physiol 2023; 43:805-816. [PMID: 36579830 DOI: 10.1093/treephys/tpac152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/15/2022] [Accepted: 12/23/2022] [Indexed: 05/13/2023]
Abstract
Phloem loading and sugar distribution are key steps for carbon partitioning in herbaceous and woody species. Although the phloem loading mechanisms in herbs are well studied, less is known for trees. It was shown for saplings of Fagus sylvatica L. and Quercus robur L. that the sucrose concentration in the phloem sap was higher than in the mesophyll cells, which suggests that phloem loading of sucrose involves active steps. However, the question remains whether this also applies for tall trees. To approach this question, tissue-specific sugar and starch contents of small and tall trees of F. sylvatica and Q. robur as well as the sugar concentration in the subcellular compartments of mesophyll cells were examined. Moreover, sucrose uptake transporters (SUTs) were analyzed by heterology expression in yeast and the tissue-specific expressions of SUTs were investigated. Sugar content in leaves of the canopy (11 and 26 m height) was up to 25% higher compared with that of leaves of small trees of F. sylvatica and Q. robur (2 m height). The sucrose concentration in the cytosol of mesophyll cells from tall trees was between 120 and 240 mM and about 4- to 8-fold lower than the sucrose concentration in the phloem sap of saplings. The analyzed SUT sequences of both tree species cluster into three types, similar to SUTs from other plant species. Heterologous expression in yeast confirmed that all analyzed SUTs are functional sucrose transporters. Moreover, all SUTs were expressed in leaves, bark and wood of the canopy and the expression levels in small and tall trees were similar. The results show that the phloem loading in leaves of tall trees of F. sylvatica and Q. robur probably involves active steps, because there is an uphill concentration gradient for sucrose. SUTs may be involved in phloem loading.
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Affiliation(s)
- Wiebke Miehe
- School of Mathematics and Natural Sciences, Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Wuppertal 42119, Germany
| | - Laura Czempik
- School of Mathematics and Natural Sciences, Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Wuppertal 42119, Germany
| | - Franz Klebl
- Department of Biology, Molecular Plant Physiology, University of Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Gertrud Lohaus
- School of Mathematics and Natural Sciences, Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Wuppertal 42119, Germany
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5
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Xu Z, Ran X, Zhang Z, Zhong M, Wang D, Li P, Fan Z. Designing a solar interfacial evaporator based on tree structures for great coordination of water transport and salt rejection. Mater Horiz 2023; 10:1737-1744. [PMID: 36799081 DOI: 10.1039/d2mh01447e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Solar interfacial evaporation has been receiving increasing attention but it is still a huge challenge to achieve excellent coordination between efficient water transport and salt rejection. Here, unlike the common wood-inspired evaporators with equal-diameter directional pores, we have constructed an integrated structure with highly connected gradient pores that mimic the xylem vessels and phloem sieve tubes found in trees. The bio-inspired structure can reduce the resistance of water transport and salt rejection in the same channel. The average transport speed of the 6.5 cm high (2 cm in diameter) porous structure reached 1.504 g s-1, and water was transported 16 cm after 100 seconds. Using multilayer graphene oxide as the photothermal conversion material, the evaporators with different heights can work for more than 9 hours under the condition of 1 sun illumination and 23 wt% brine without any salt crystallization, and the evaporation rates range from 3.28 to 4.51 kg m-2 h-1, with the highest energy utilization efficiency of about 80%. When used in heavy metal treatment, the rejection was greater than 99.99%. This research provides a simple but innovative design idea for evaporators and is expected to further expand the application of solar interfacial evaporation.
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Affiliation(s)
- Zhicheng Xu
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
| | - Xueqin Ran
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
| | - Zhijie Zhang
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
| | - Mingfeng Zhong
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
| | - Da Wang
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, 510640, China
| | - Pengping Li
- Key Laboratory of Harbor and Marine Structure Durability Technology Ministry of Communications, Guangzhou, 510230, China
| | - Zhihong Fan
- Key Laboratory of Harbor and Marine Structure Durability Technology Ministry of Communications, Guangzhou, 510230, China
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6
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Chen J, Jiang T, Jiang J, Deng L, Liu Y, Zhong Z, Fu H, Yang B, Zhang L. The chloroplast GATA-motif of Mahonia bealei participates in alkaloid-mediated photosystem inhibition during dark to light transition. J Plant Physiol 2023; 280:153894. [PMID: 36525836 DOI: 10.1016/j.jplph.2022.153894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Mahonia bealei and Mahonia fortunei are important plant resources in Traditional Chinese Medicine that are valued for their high levels of benzylisoquinoline alkaloids (BIAs). Although the phytotoxic activity of BIAs has been recognized, information is limited on the mechanism of action by which these compounds regulate photosynthetic activity. Here, we performed comparative chloroplast genome analysis to examine insertions and deletions in the two species. We found a GATA-motif located in the promoter region of the ndhF gene of only M. bealei. K-mer frequency-based diversity analysis illustrated the close correlation between the GATA-motif and leaf phenotype. We found that the GATA-motif significantly inhibits GUS gene expression in tobacco during the dark-light transition (DLT). The expression of ndhF was downregulated in M. bealei and upregulated in M. fortunei during the DLT. NDH-F activity was remarkably decreased and exhibited a significant negative correlation with BIA levels in M. bealei during the DLT. Furthermore, the NADPH produced through photosynthetic metabolism was found to decrease in M. bealei during the DLT. Taken together, our results indicate that this GATA-motif might act as the functional site by which BIAs inhibit photosynthetic metabolism through downregulating ndhF expression during the DLT.
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Affiliation(s)
- Jiaqi Chen
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Tianfu Jiang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Jiajun Jiang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Linfang Deng
- The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, 310005, China
| | - Yiting Liu
- College of Agronomy and Biotechnology, Southwest University, Chongqing, 400715, China
| | - Zhuoheng Zhong
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Hongwei Fu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Bingxian Yang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Lin Zhang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
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7
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Liu C, Tang M, Zhang F, Lei F, Li P, Wang K, Zeng H, Jiang J. Facile Access to Gleditsia microphylla Galactomannan Hydrogel with Rapid Self-Repair Capacity and Multicyclic Water-Retaining Performance of Sandy Soil. Polymers (Basel) 2022; 14. [PMID: 36559797 DOI: 10.3390/polym14245430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Sandy soil has poor water-holding performance, making it difficult for plants to survive, which worsens the deterioration of the ecological environment. Therefore, borax cross-linked Gleditsia microphylla galactomannan hydrogel (GMGH) was prepared, and its practicability as a water-retaining agent was analyzed. GMGH exhibited fast self-healing performance (150 s, ≈100%) and a high swelling index (88.70 g/g in pH 9). The feasibility of improving the water absorption and retention properties of sandy soil was explored by mixing different proportions (0.1, 0.3, 0.5 wt % sandy soil) of GMGH and sandy soil. The results showed that sandy soil had a more porous structure after adding 0.5 wt % GMGH, and its water absorption index increased from 15.68 to 38.12%. In an artificial climate box, the water-holding time of the sandy soil was extended from 3 to 23.5 days, and the cycles of water absorption and retention were more than 10 times. Therefore, GMGH has broad application prospects as a potential water-retaining agent for desertification control.
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Tang Y, Yin S, Pace MR, Gerolamo CS, Nogueira A, Zuntini AR, Lohmann LG, Plath M, Liesche J. Diameters of phloem sieve elements can predict stem growth rates of woody plants. Tree Physiol 2022; 42:1560-1569. [PMID: 35218199 DOI: 10.1093/treephys/tpac022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Understanding forest dynamics is crucial to addressing climate change and reforestation challenges. Plant anatomy can help predict growth rates of woody plants, contributing key information on forest dynamics. Although features of the water-transport system (xylem) have long been used to predict plant growth, the potential contribution of carbon-transporting tissue (phloem) remains virtually unexplored. Here, we use data from 347 woody plant species to investigate whether species-specific stem diameter growth rates can be predicted by the diameter of both the xylem and phloem conducting cells when corrected for phylogenetic relatedness. We found positive correlations between growth rate, phloem sieve element diameter and xylem vessel diameter in liana species sampled in the field. Moreover, we obtained similar results for data extracted from the Xylem Database, an online repository of functional, anatomical and image data for woody plant species. Information from this database confirmed the correlation of sieve element diameter and growth rate across woody plants of various growth forms. Furthermore, we used data subsets to explore potential influences of biomes, growth forms and botanical family association. Subsequently, we combined anatomical and geoclimatic data to train an artificial neural network to predict growth rates. Our results demonstrate that sugar transport architecture is associated with growth rate to a similar degree as water-transport architecture. Furthermore, our results illustrate the potential value of artificial neural networks for modeling plant growth under future climatic scenarios.
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Affiliation(s)
- Yunjia Tang
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
| | - Shijiao Yin
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
- Biomass Energy Center for Arid Lands, Northwest A & F University, Yangling 712100, China
- State Key Laboratory of Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
| | - Marcelo R Pace
- Universidad Nacional Autónoma de México, Instituto de Biología, Departamento de Botánica, Circuito Zona Deportiva s.n., Apartado Postal 70-367, Ciudad Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Caian S Gerolamo
- Universidade de São Paulo, Instituto de Biociências, Departamento de Botânica, Rua do Matão, 277, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Anselmo Nogueira
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas (CCNH), Rua Arcturus, 03, São Bernardo do Campo, SP 09606-070, Brazil
| | | | - Lúcia G Lohmann
- Universidade de São Paulo, Instituto de Biociências, Departamento de Botânica, Rua do Matão, 277, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Martin Plath
- Northwest A&F University, College of Animal Science and Technology, Yangling 712100, China
| | - Johannes Liesche
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
- Biomass Energy Center for Arid Lands, Northwest A & F University, Yangling 712100, China
- State Key Laboratory of Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
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9
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Nakad M, Domec JC, Sevanto S, Katul G. Radial-axial transport coordination enhances sugar translocation in the phloem vasculature of plants. Plant Physiol 2022; 189:2061-2071. [PMID: 35588257 PMCID: PMC9343002 DOI: 10.1093/plphys/kiac231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/27/2022] [Indexed: 05/21/2023]
Abstract
Understanding mass transport of photosynthates in the phloem of plants is necessary for predicting plant carbon allocation, productivity, and responses to water and thermal stress. Several hypotheses about optimization of phloem structure and function and limitations of phloem transport under drought have been proposed and tested with models and anatomical data. However, the true impact of radial water exchange of phloem conduits with their surroundings on mass transport of photosynthates has not been addressed. Here, the physics of the Munch mechanism of sugar transport is re-evaluated to include local variations in viscosity resulting from the radial water exchange in two dimensions (axial and radial) using transient flow simulations. Model results show an increase in radial water exchange due to a decrease in sap viscosity leading to increased sugar front speed and axial mass transport across a wide range of phloem conduit lengths. This increase is around 40% for active loaders (e.g. crops) and around 20% for passive loaders (e.g. trees). Thus, sugar transport operates more efficiently than predicted by previous models that ignore these two effects. A faster front speed leads to higher phloem resiliency under drought because more sugar can be transported with a smaller pressure gradient.
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Affiliation(s)
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, Gradignan 33175, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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10
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Petit G, Zambonini D, Hesse BD, Häberle K. No xylem phenotypic plasticity in mature Picea abies and Fagus sylvatica trees after 5 years of throughfall precipitation exclusion. Glob Chang Biol 2022; 28:4668-4683. [PMID: 35555836 PMCID: PMC9325500 DOI: 10.1111/gcb.16232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Forest trees are experiencing increasing frequency and intensity of drought events with climate change. We investigated xylem and phloem traits from mature Fagus sylvatica and Picea abies trees after 5 years of complete exclusion of throughfall precipitation during the growing season. Xylem and phloem anatomy, leaf and branch biomass were analysed along top branches of ~1.5 m lenght in 5 throughfall precipitation excluded (TE) and 5 control (CO) trees of both beech and spruce. Xylem traits were analysed on wood cores extracted from the stem at breast height. In the top branches of both species, the lumen diameter (or area) of xylem and phloem conduits did not differ between TE and CO trees. At breast height, TE trees of both species produced narrower xylem rings and conduits. While allocation to branch (BM) and needle biomass (LM) did not change between TE and CO in P. abies, TE F. sylvatica trees allocated proportionally more biomass to leaves (LM) than BM compared with CO. Despite artificial drought increased the mortality in the TE plots, our results revealed no changes in both xylem and phloem anatomies, undermining the hypothesis that successful acclimation to drought would primarily involve increased resistance against air embolism.
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Affiliation(s)
- Giai Petit
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Dario Zambonini
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Benjamin D. Hesse
- Land Surface‐Atmosphere InteractionsTechnical University of Munich, School of Life SciencesFreisingGermany
| | - Karl‐Heinz Häberle
- Chair of Restoration EcologyTechnical University of Munich, School of Life SciencesFreisingGermany
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Losada JM, He Z, Holbrook NM. Sieve tube structural variation in Austrobaileya scandens and its significance for lianescence. Plant Cell Environ 2022; 45:2460-2475. [PMID: 35606891 PMCID: PMC9540405 DOI: 10.1111/pce.14361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 04/15/2022] [Accepted: 04/23/2022] [Indexed: 06/15/2023]
Abstract
Lianas combine large leaf areas with slender stems, features that require an efficient vascular system. The only extant member of the Austrobaileyaceae is an endemic twining liana of the tropical Australian forests with well-known xylem hydraulics, but the vascular phloem continuum aboveground remains understudied. Microscopy analysis across leaf vein orders and stems of Austrobaileya scandens revealed a low foliar xylem:phloem ratio, with isodiametric vascular elements along the midrib, but tapered across vein orders. Sieve plate pore radii increased from 0.08 µm in minor veins to 0.12 µm in the petiole, but only to 0.20 µm at the stem base, tens of metres away. In easily bent searcher branches, phloem conduits have pectin-rich walls and simple plates, whereas in twining stems, conduits were connected through highly angled and densely porated sieve plates. The hydraulic resistance of phloem conduits in the twisted and elongated stems of A. scandens is large compared with trees of similar stature; phloem hydraulic resistance decreases from leaves to stems, consistent with the efficient delivery of photoassimilates from sources under Münch predictions. Sink strength of a continuously growing canopy might be stronger than in self-supporting understory plants, favoring resource allocation to aerial organs and the attainment of vertical stature.
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Affiliation(s)
- Juan M. Losada
- Institute for Mediterranean and Subtropical Horticulture ‘La Mayora’—CSIC—UMAAvda. Dr. Wienberg s/nAlgarrobo‐CostaMálaga29750Spain
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
| | - Zhe He
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
| | - N. Michele Holbrook
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
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12
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Miras M, Pottier M, Schladt TM, Ejike JO, Redzich L, Frommer WB, Kim JY. Plasmodesmata and their role in assimilate translocation. J Plant Physiol 2022; 270:153633. [PMID: 35151953 DOI: 10.1016/j.jplph.2022.153633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
During multicellularization, plants evolved unique cell-cell connections, the plasmodesmata (PD). PD of angiosperms are complex cellular domains, embedded in the cell wall and consisting of multiple membranes and a large number of proteins. From the beginning, it had been assumed that PD provide passage for a wide range of molecules, from ions to metabolites and hormones, to RNAs and even proteins. In the context of assimilate allocation, it has been hypothesized that sucrose produced in mesophyll cells is transported via PD from cell to cell down a concentration gradient towards the phloem. Entry into the sieve element companion cell complex (SECCC) is then mediated on three potential routes, depending on the species and conditions, - either via diffusion across PD, after conversion to raffinose via PD using a polymer trap mechanism, or via a set of transporters which secrete sucrose from one cell and secondary active uptake into the SECCC. Multiple loading mechanisms can likely coexist. We here review the current knowledge regarding photoassimilate transport across PD between cells as a prerequisite for translocation from leaves to recipient organs, in particular roots and developing seeds. We summarize the state-of-the-art in protein composition, structure, transport mechanism and regulation of PD to apprehend their functions in carbohydrate allocation. Since many aspects of PD biology remain elusive, we highlight areas that require new approaches and technologies to advance our understanding of these enigmatic and important cell-cell connections.
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Affiliation(s)
- Manuel Miras
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Mathieu Pottier
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - T Moritz Schladt
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - J Obinna Ejike
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Laura Redzich
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Wolf B Frommer
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany; Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
| | - Ji-Yun Kim
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
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13
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Potkay A, Hölttä T, Trugman AT, Fan Y. Turgor-limited predictions of tree growth, height and metabolic scaling over tree lifespans. Tree Physiol 2022; 42:229-252. [PMID: 34296275 DOI: 10.1093/treephys/tpab094] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
Increasing evidence suggests that tree growth is sink-limited by environmental and internal controls rather than by carbon availability. However, the mechanisms underlying sink-limitations are not fully understood and thus not represented in large-scale vegetation models. We develop a simple, analytically solved, mechanistic, turgor-driven growth model (TDGM) and a phloem transport model (PTM) to explore the mechanics of phloem transport and evaluate three hypotheses. First, phloem transport must be explicitly considered to accurately predict turgor distributions and thus growth. Second, turgor-limitations can explain growth-scaling with size (metabolic scaling). Third, turgor can explain realistic growth rates and increments. We show that mechanistic, sink-limited growth schemes based on plant turgor limitations are feasible for large-scale model implementations with minimal computational demands. Our PTM predicted nearly uniform sugar concentrations along the phloem transport path regardless of phloem conductance, stem water potential gradients and the strength of sink-demands contrary to our first hypothesis, suggesting that phloem transport is not limited generally by phloem transport capacity per se but rather by carbon demand for growth and respiration. These results enabled TDGM implementation without explicit coupling to the PTM, further simplifying computation. We test the TDGM by comparing predictions of whole-tree growth rate to well-established observations (site indices) and allometric theory. Our simple TDGM predicts realistic tree heights, growth rates and metabolic scaling over decadal to centurial timescales, suggesting that tree growth is generally sink and turgor limited. Like observed trees, our TDGM captures tree-size- and resource-based deviations from the classical ¾ power-law metabolic scaling for which turgor is responsible.
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Affiliation(s)
- Aaron Potkay
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08854, USA
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki FI-00014, Finland
| | - Anna T Trugman
- Department of Geography, University of California at Santa Barbara, Santa Barbara, CA 93106, USA
| | - Ying Fan
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08854, USA
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14
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Burridge JD, Grondin A, Vadez V. Optimizing Crop Water Use for Drought and Climate Change Adaptation Requires a Multi-Scale Approach. Front Plant Sci 2022; 13:824720. [PMID: 35574091 PMCID: PMC9100818 DOI: 10.3389/fpls.2022.824720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/11/2022] [Indexed: 05/09/2023]
Abstract
Selection criteria that co-optimize water use efficiency and yield are needed to promote plant productivity in increasingly challenging and variable drought scenarios, particularly dryland cereals in the semi-arid tropics. Optimizing water use efficiency and yield fundamentally involves transpiration dynamics, where restriction of maximum transpiration rate helps to avoid early crop failure, while maximizing grain filling. Transpiration restriction can be regulated by multiple mechanisms and involves cross-organ coordination. This coordination involves complex feedbacks and feedforwards over time scales ranging from minutes to weeks, and from spatial scales ranging from cell membrane to crop canopy. Aquaporins have direct effect but various compensation and coordination pathways involve phenology, relative root and shoot growth, shoot architecture, root length distribution profile, as well as other architectural and anatomical aspects of plant form and function. We propose gravimetric phenotyping as an integrative, cross-scale solution to understand the dynamic, interwoven, and context-dependent coordination of transpiration regulation. The most fruitful breeding strategy is likely to be that which maintains focus on the phene of interest, namely, daily and season level transpiration dynamics. This direct selection approach is more precise than yield-based selection but sufficiently integrative to capture attenuating and complementary factors.
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Affiliation(s)
- James D. Burridge
- DIADE Group, Cereal Root Systems, Institute de Recherche pour le Développement/Université de Montpellier, Montpellier, France
- *Correspondence: James D. Burridge,
| | - Alexandre Grondin
- DIADE Group, Cereal Root Systems, Institute de Recherche pour le Développement/Université de Montpellier, Montpellier, France
- Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Laboratoire Mixte International, Dakar, Senegal
- Centre d’Étude Régional pour l’Amélioration de l’Adaptation à la Sécheresse, Thiès, Senegal
| | - Vincent Vadez
- DIADE Group, Cereal Root Systems, Institute de Recherche pour le Développement/Université de Montpellier, Montpellier, France
- Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Laboratoire Mixte International, Dakar, Senegal
- Centre d’Étude Régional pour l’Amélioration de l’Adaptation à la Sécheresse, Thiès, Senegal
- International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Patancheru, India
- Vincent Vadez,
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15
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Dewar R, Hölttä T, Salmon Y. Exploring optimal stomatal control under alternative hypotheses for the regulation of plant sources and sinks. New Phytol 2022; 233:639-654. [PMID: 34637543 DOI: 10.1111/nph.17795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Experimental evidence that nonstomatal limitations to photosynthesis (NSLs) correlate with leaf sugar and/or leaf water status suggests the possibility that stomata adjust to maximise photosynthesis through a trade-off between leaf CO2 supply and NSLs, potentially involving source-sink interactions. However, the mechanisms regulating NSLs and sink strength, as well as their implications for stomatal control, remain uncertain. We used an analytically solvable model to explore optimal stomatal control under alternative hypotheses for source and sink regulation. We assumed that either leaf sugar concentration or leaf water potential regulates NSLs, and that either phloem turgor pressure or phloem sugar concentration regulates sink phloem unloading. All hypotheses led to realistic stomatal responses to light, CO2 and air humidity, including conservative behaviour for the intercellular-to-atmospheric CO2 concentration ratio. Sugar-regulated and water-regulated NSLs are distinguished by the presence/absence of a stomatal closure response to changing sink strength. Turgor-regulated and sugar-regulated phloem unloading are distinguished by the presence/absence of stomatal closure under drought and avoidance/occurrence of negative phloem turgor. Results from girdling and drought experiments on Pinus sylvestris, Betula pendula, Populus tremula and Picea abies saplings are consistent with optimal stomatal control under sugar-regulated NSLs and turgor-regulated unloading. Our analytical results provide a simple representation of stomatal responses to above-ground and below-ground environmental factors and sink activity.
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Affiliation(s)
- Roderick Dewar
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
| | - Yann Salmon
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
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16
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Gersony JT, McClelland A, Holbrook NM. Raman spectroscopy reveals high phloem sugar content in leaves of canopy red oak trees. New Phytol 2021; 232:418-424. [PMID: 33991343 DOI: 10.1111/nph.17465] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
A robust understanding of phloem functioning in tall trees evades us because current methods for collecting phloem sap do not lend themselves to measuring actively photosynthesizing canopy leaves. We show that Raman spectroscopy can be used as a quantitative tool to assess sucrose concentration in leaf samples. Specifically, we found that Raman spectroscopy can predict physiologically relevant sucrose concentrations (adjusted R2 of 0.9) in frozen leaf extract spiked with sucrose. We then apply this method to estimate sieve element sucrose concentration in rapidly frozen petioles of canopy red oak (Quercus rubra) trees and found that sucrose concentrations are > 1100 mM at midday and midnight. This concentration is predicted to generate a sieve element turgor pressure high enough to generate bulk flow through the phloem, but is potentially too high to allow for sucrose diffusion from photosynthetic cells. Our findings support the Münch hypothesis for phloem transport once the carbon is in the phloem and challenge the passive-loading hypothesis for carbon movement into the phloem for red oak. This study provides the first ˜in-situ (frozen in the functioning state) source sieve element sucrose concentration characterization in any plant, opening a new avenue for investigation of phloem functioning.
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Affiliation(s)
- Jess T Gersony
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Arthur McClelland
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, 02138, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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17
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Barceló-Anguiano M, Holbrook NM, Hormaza JI, Losada JM. Changes in ploidy affect vascular allometry and hydraulic function in Mangifera indica trees. Plant J 2021; 108:541-554. [PMID: 34403543 DOI: 10.1111/tpj.15460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
The enucleated vascular elements of the xylem and the phloem offer an excellent system to test the effect of ploidy on plant function because variation in vascular geometry has a direct influence on transport efficiency. However, evaluations of conduit sizes in polyploid plants have remained elusive, most remarkably in woody species. We used a combination of molecular, physiological and microscopy techniques to model the hydraulic resistance between source and sinks in tetraploid and diploid mango trees. Tetraploids exhibited larger chloroplasts, mesophyll cells and stomatal guard cells, resulting in higher leaf elastic modulus and lower dehydration rates, despite the high water potentials of both ploidies in the field. Both the xylem and the phloem displayed a scaling of conduits with ploidy, revealing attenuated hydraulic resistance in tetraploids. Conspicuous wall hygroscopic moieties in the cells involved in transpiration and transport indicate a role in volumetric adjustments as a result of turgor change in both ploidies. In autotetraploids, the enlargement of organelles, cells and tissues, which are critical for water and photoassimilate transport at long distances, point to major physiological novelties associated with whole-genome duplication.
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Affiliation(s)
- Miguel Barceló-Anguiano
- Institute for Mediterranean and Subtropical Horticulture 'La Mayora' - CSIC - UMA, Avda. Dr. Wienberg s/n, Málaga, 29750, Spain
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
| | - José I Hormaza
- Institute for Mediterranean and Subtropical Horticulture 'La Mayora' - CSIC - UMA, Avda. Dr. Wienberg s/n, Málaga, 29750, Spain
| | - Juan M Losada
- Institute for Mediterranean and Subtropical Horticulture 'La Mayora' - CSIC - UMA, Avda. Dr. Wienberg s/n, Málaga, 29750, Spain
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
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18
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Ray DM, Savage JA. Seasonal changes in temperate woody plant phloem anatomy and physiology: implications for long-distance transport. AoB Plants 2021; 13:plab028. [PMID: 34234934 PMCID: PMC8255074 DOI: 10.1093/aobpla/plab028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
Seasonal changes in climate are accompanied by shifts in carbon allocation and phenological changes in woody angiosperms, the timing of which can have broad implications for species distributions, interactions and ecosystem processes. During critical transitions from autumn to winter and winter to spring, physiological and anatomical changes within the phloem could impose a physical limit on the ability of woody angiosperms to transport carbon and signals. There is a paucity of the literature that addresses tree (floral or foliar) phenology, seasonal phloem anatomy and seasonal phloem physiology together, so our knowledge of how carbon transport could fluctuate seasonally, especially in temperate climates is limited. We review phloem phenology focussing on how sieve element anatomy and phloem sap flow could affect carbon availability throughout the year with a focus on winter. To investigate whether flow is possible in the winter, we construct a simple model of phloem sap flow and investigate how changes to the sap concentration, pressure gradient and sieve plate pores could influence flow during the winter. Our model suggests that phloem transport in some species could occur year-round, even in winter, but current methods for measuring all the parameters surrounding phloem sap flow make it difficult to test this hypothesis. We highlight outstanding questions that remain about phloem functionality in the winter and emphasize the need for new methods to address gaps in our knowledge about phloem function.
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Affiliation(s)
- Dustin M Ray
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
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19
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Barceló-Anguiano M, Hormaza JI, Losada JM. Conductivity of the phloem in mango (Mangifera indica L.). Hortic Res 2021; 8:150. [PMID: 34193860 PMCID: PMC8245510 DOI: 10.1038/s41438-021-00584-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Mango (Mangifera indica L., Anacardiaceae), the fifth most consumed fruit worldwide, is one of the most important fruit crops in tropical regions, but its vascular anatomy is quite unexplored. Previous studies examined the xylem structure in the stems of mango, but the anatomy of the phloem has remained elusive, leaving the long-distance transport of photoassimilates understudied. We combined fluorescence and electron microscopy to evaluate the structure of the phloem tissue in the tapering branches of mango trees, and used this information to describe the hydraulic conductivity of its sieve tube elements following current models of fluid transport in trees. We revealed that the anatomy of the phloem changes from current year branches, where it was protected by pericyclic fibres, to older ones, where the lack of fibres was concomitant with laticiferous canals embedded in the phloem tissue. Callose was present in the sieve plates, but also in the walls of the phloem sieve cells, making them discernible from other phloem cells. A scaling geometry of the sieve tube elements-including the number of sieve areas and the pore size across tapering branches-resulted in an exponential conductivity towards the base of the tree. These evaluations in mango fit with previous measurements of the phloem architecture in the stems of forest trees, suggesting that, despite agronomic management, the phloem sieve cells scale with the tapering branches. The pipe model theory applied to the continuous tubing system of the phloem appears as a good approach to understand the hydraulic transport of photoassimilates in fruit trees.
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Affiliation(s)
- Miguel Barceló-Anguiano
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM La Mayora-CSIC-UMA), Avda Dr. Wienberg s/n. 29750, Algarrobo-Costa, Málaga, Spain
| | - José I Hormaza
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM La Mayora-CSIC-UMA), Avda Dr. Wienberg s/n. 29750, Algarrobo-Costa, Málaga, Spain
| | - Juan M Losada
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM La Mayora-CSIC-UMA), Avda Dr. Wienberg s/n. 29750, Algarrobo-Costa, Málaga, Spain.
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20
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Young SNR, Sack L, Sporck-Koehler MJ, Lundgren MR. Why is C4 photosynthesis so rare in trees? J Exp Bot 2020; 71:4629-4638. [PMID: 32409834 PMCID: PMC7410182 DOI: 10.1093/jxb/eraa234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/12/2020] [Indexed: 05/08/2023]
Abstract
Since C4 photosynthesis was first discovered >50 years ago, researchers have sought to understand how this complex trait evolved from the ancestral C3 photosynthetic machinery on >60 occasions. Despite its repeated emergence across the plant kingdom, C4 photosynthesis is notably rare in trees, with true C4 trees only existing in Euphorbia. Here we consider aspects of the C4 trait that could limit but not preclude the evolution of a C4 tree, including reduced quantum yield, increased energetic demand, reduced adaptive plasticity, evolutionary constraints, and a new theory that the passive symplastic phloem loading mechanism observed in trees, combined with difficulties in maintaining sugar and water transport over a long pathlength, could make C4 photosynthesis largely incompatible with the tree lifeform. We conclude that the transition to a tree habit within C4 lineages as well as the emergence of C4 photosynthesis within pre-existing trees would both face a series of challenges that together explain the global rarity of C4 photosynthesis in trees. The C4 trees in Euphorbia are therefore exceptional in how they have circumvented every potential barrier to the rare C4 tree lifeform.
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Affiliation(s)
- Sophie N R Young
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Marjorie R Lundgren
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
- Correspondence:
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21
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Clerx LE, Rockwell FE, Savage JA, Holbrook NM. Ontogenetic scaling of phloem sieve tube anatomy and hydraulic resistance with tree height in Quercus rubra. Am J Bot 2020; 107:852-863. [PMID: 32468597 DOI: 10.1002/ajb2.1481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
PREMISE The dimensions of phloem sieve elements have been shown to vary as a function of tree height, decreasing hydraulic resistance as the transport pathway lengthens. However, little is known about ontogenetic patterns of sieve element scaling. Here we examine within a single species (Quercus rubra) how decreases in hydraulic resistance with distance from the plant apex are mediated by overall plant size. METHODS We sampled and imaged phloem tissue at multiple heights along the main stem and in the live crown of four size classes of trees using fluorescence and scanning electron microscopy. Sieve element length and radius, the number of sieve areas per compound plate, pore number, and pore radius were used to calculate total hydraulic resistance at each sampling location. RESULTS Sieve element length varied with tree size, while sieve element radius, sieve pore radius, and the number of sieve areas per compound plate varied with sampling position. When data from all size classes were aggregated, all four variables followed a power-law trend with distance from the top of the tree. The net effect of these ontogenetic scalings was to make total hydraulic sieve tube resistance independent of tree height from 0.5 to over 20 m. CONCLUSIONS Sieve element development responded to two pieces of information, tree size and distance from the apex, in a manner that conserved total sieve tube resistance across size classes. A further differentiated response between the phloem in the live crown and in the main stem is also suggested.
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Affiliation(s)
- Laura E Clerx
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota, Duluth, MN, 55812, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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22
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Kiorapostolou N, Camarero JJ, Carrer M, Sterck F, Brigita B, Sangüesa-Barreda G, Petit G. Scots pine trees react to drought by increasing xylem and phloem conductivities. Tree Physiol 2020; 40:774-781. [PMID: 32186730 DOI: 10.1093/treephys/tpaa033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 02/29/2020] [Accepted: 03/12/2020] [Indexed: 06/10/2023]
Abstract
Drought limits the long-distance transport of water in the xylem due to the reduced leaf-to-soil water potential difference and possible embolism-related losses of conductance and of sugars in the phloem due to the higher viscosity of the dehydrated sugary solution. This condition can have cascading effects in water and carbon (C) fluxes that may ultimately cause tree death. We hypothesize that the maintenance of xylem and phloem conductances is fundamental for survival also under reduced resource availability, when trees may produce effective and low C cost anatomical adjustments in the xylem and phloem close to the treetop where most of the hydraulic resistance is concentrated. We analyzed the treetop xylem and phloem anatomical characteristics in coexisting Scots pine trees, symptomatic and non-symptomatic of drought-induced dieback. We selected the topmost 55 cm of the main stem and selected several sampling positions at different distances from the stem apex to test for differences in the axial patterns between the two groups of trees. We measured the annual ring area, the tracheid hydraulic diameter (Dh) and cell wall thickness (CWT), the conductive phloem area and the average lumen diameter of the 20 largest phloem sieve cells (Dph). Declining trees grew less than the non-declining ones, and despite the similar axial scaling of anatomical traits, had larger Dh and lower CWT. Moreover, declining trees had wider Dph. Our results demonstrate that even under drought stress, maintenance of xylem and phloem efficiencies is of primary importance for survival, even if producing fewer larger tracheids may lead to a xylem more vulnerable to embolism formation.
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Affiliation(s)
- Natasa Kiorapostolou
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - J Julio Camarero
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
| | - Marco Carrer
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Frank Sterck
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Brigita Brigita
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Gabriel Sangüesa-Barreda
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
- Depto Ciencias Agroforestales, iuFOR-EiFAB, University of Valladolid, Campus Duques de Soria s/n, Soria E-42004, Spain
| | - Giai Petit
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
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Huang Z, Huang X, Fan J, Eichhorn M, An F, Chen B, Cao L, Zhu Z, Yun T. Retrieval of Aerodynamic Parameters in Rubber Tree Forests Based on the Computer Simulation Technique and Terrestrial Laser Scanning Data. Remote Sensing 2020; 12:1318. [DOI: 10.3390/rs12081318] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Rubber trees along the southeast coast of China always suffer severe damage from hurricanes. Quantitative assessments of the capacity for wind resistance of various rubber tree clones are currently lacking. We focus on a vulnerability assessment of rubber trees of different clones under wind disturbance impacts by employing multidisciplinary approaches incorporating scanned points, aerodynamics, machine learning and computer graphics. Point cloud data from two typical rubber trees belonging to different clones (PR107 and CATAS 7-20-59) were collected using terrestrial laser scanning, and a connection chain of tree skeletons was constructed using a clustering algorithm of machine learning. The concept of foliage clumps based on the trunk and first-order branches was first proposed to optimize rubber tree plot 3D modelling for simulating the wind field and assessing the wind-related parameters. The results from the obtained phenotypic traits show that the variable leaf area index and included angle between the branches and trunk result in variations in the topological structure and gap fraction of tree crowns, respectively, which are the major influencing factors relevant to the rubber tree’s capacity to resist hurricane strikes. The aerodynamics analysis showed that the maximum dynamic pressure, wind velocity and turbulent intensity of the wind-related parameters in rubber tree plots of clone PR107 (300 Pa, 30 m/s and 15%) are larger than that in rubber tree plots of clone CATAS-7-20-59 (120 Pa, 18 m/s and 5%), which results in a higher probability of local strong cyclone occurrence and a higher vulnerability to hurricane damage.
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24
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Oren I, Mannerheim N, Dumbur R, Fangmeier A, Buchmann N, Grünzweig JM. Patterns and dynamics of canopy-root coupling in tropical tree saplings vary with light intensity but not with root depth. New Phytol 2020; 225:727-739. [PMID: 31469437 DOI: 10.1111/nph.16153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Carbon (C) dynamics in canopy and roots influence whole-tree carbon fluxes, but little is known about canopy regulation of tree-root activity. Here, the patterns and dynamics of canopy-root C coupling are assessed in tropical trees. Large aeroponics facility was used to study the root systems of Ceiba pentandra and Khaya anthotheca saplings directly at different light intensities. In Ceiba, root respiration (Rr ) co-varied with photosynthesis (An ) in large saplings (3-to-7-m canopy-root axis) at high-light, but showed no consistent pattern at low-light. At medium-light and in small saplings (c. 1-m axis), Rr tended to decrease transiently towards midday. Proximal roots had higher Rr and nonstructural carbohydrate concentrations than distal roots, but canopy-root coupling was unaffected by root location. In medium-sized Khaya, no Rr pattern was observed, and in both species, Rr was unrelated to temperature. The early-afternoon increase in Rr suggests that canopy-root coupling is based on mass flow of newly fixed C in the phloem, whereas the early-morning rise in Rr with An indicates an additional coupling signal that travels faster than the phloem sap. In large saplings and potentially also in higher trees, light and possibly additional environmental factors control the diurnal patterns of canopy-root coupling, irrespective of root location.
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Affiliation(s)
- Israel Oren
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, 7610001, Rehovot, Israel
| | - Neringa Mannerheim
- Institute of Agricultural Sciences, ETH Zürich, Universitätstrasse 2, 8092, Zürich, Switzerland
| | - Rita Dumbur
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, 7610001, Rehovot, Israel
| | - Andreas Fangmeier
- Institute of Landscape and Plant Ecology, University of Hohenheim, August-von-Hartmann-Str. 3, 70599, Stuttgart, Germany
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zürich, Universitätstrasse 2, 8092, Zürich, Switzerland
| | - José M Grünzweig
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, 7610001, Rehovot, Israel
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25
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Furze ME, Drake JE, Wiesenbauer J, Richter A, Pendall E. Carbon isotopic tracing of sugars throughout whole-trees exposed to climate warming. Plant Cell Environ 2019; 42:3253-3263. [PMID: 31335973 DOI: 10.1111/pce.13625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Trees allocate C from sources to sinks by way of a series of processes involving carbohydrate transport and utilization. Yet these dynamics are not well characterized in trees, and it is unclear how these dynamics will respond to a warmer world. Here, we conducted a warming and pulse-chase experiment on Eucalyptus parramattensis growing in a whole-tree chamber system to test whether warming impacts carbon allocation by increasing the speed of carbohydrate dynamics. We pulse-labelled large (6-m tall) trees with 13 C-CO2 to follow recently fixed C through different organs by using compound-specific isotope analysis of sugars. We then compared concentrations and mean residence times of individual sugars between ambient and warmed (+3°C) treatments. Trees dynamically allocated 13 C-labelled sugars throughout the aboveground-belowground continuum. We did not, however, find a significant treatment effect on C dynamics, as sugar concentrations and mean residence times were not altered by warming. From the canopy to the root system, 13 C enrichment of sugars decreased, and mean residence times increased, reflecting dilution and mixing of recent photoassimilates with older reserves along the transport pathway. Our results suggest that a locally endemic eucalypt was seemingly able to adjust its physiology to warming representative of future temperature predictions for Australia.
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Affiliation(s)
- Morgan E Furze
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - John E Drake
- Department of Forest and Natural Resources Management, College of Environmental Science and Forestry, State University of New York, Syracuse, New York, 13210
| | - Julia Wiesenbauer
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, 1010, Austria
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, 1010, Austria
| | - Elise Pendall
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia
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26
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Sevanto S. Methods for Assessing the Role of Phloem Transport in Plant Stress Responses. Methods Mol Biol 2019; 2014:311-336. [PMID: 31197806 DOI: 10.1007/978-1-4939-9562-2_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Delivery of carbohydrates to tissues that need them under stress is important for plant defenses and survival. Yet, little is known on how phloem function is altered under stress, and how that influences plant responses to stress. This is because phloem is a challenging tissue to study. It consists of cells of various types with soft cell walls, and the cells show strong wounding reactions to protect their integrity, making both imaging and functional studies challenging. This chapter summarizes theories on how phloem transport is affected by stress and presents methods that have been used to gain the current knowledge. These techniques range from tracer studies and imaging to carbon balance and anatomical analyses. Advances in these techniques in the recent years have considerably increased our ability to investigate phloem function, and application of the new methods on plant stress studies will help provide a more comprehensive picture of phloem function and its limitations under stress.
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Affiliation(s)
- Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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27
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Stanfield RC, Schulte PJ, Randolph KE, Hacke UG. Computational models evaluating the impact of sieve plates and radial water exchange on phloem pressure gradients. Plant Cell Environ 2019; 42:466-479. [PMID: 30074610 DOI: 10.1111/pce.13414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/20/2018] [Indexed: 05/06/2023]
Abstract
The sugar conducting phloem in angiosperms is a high resistance pathway made up of sieve elements bounded by sieve plates. The high resistance generated by sieve plates may be a trade-off for promoting quick sealing in the event of injury. However, previous modeling efforts have demonstrated a wide variation in the contribution of sieve plates towards total sieve tube resistance. In the current study, we generated high resolution scanning electron microscope images of sieve plates from balsam poplar and integrated them into a mathematical model using Comsol Multiphysics software. We found that sieve plates contribute upwards of 85% towards total sieve tube resistance. Utilizing the Navier-Stokes equations, we found that oblong pores may create over 50% more resistance in comparison with round pores of the same area. Although radial water flows in phloem sieve tubes have been previously considered, their impact on alleviating pressure gradients has not been fully studied. Our novel simulations find that radial water flow can reduce pressure requirements by half in comparison with modeled sieve tubes with no radial permeability. We discuss the implication that sieve tubes may alleviate pressure requirements to overcome high resistances by regulating their membrane permeability along the entire transport pathway.
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Affiliation(s)
- Ryan C Stanfield
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Paul J Schulte
- School of Life Sciences, University of Nevada-Las Vegas, Las Vegas, Nevada
| | - Katie E Randolph
- School of Life Sciences, University of Nevada-Las Vegas, Las Vegas, Nevada
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
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28
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Kiorapostolou N, Petit G. Similarities and differences in the balances between leaf, xylem and phloem structures in Fraxinus ornus along an environmental gradient. Tree Physiol 2019; 39:234-242. [PMID: 30189046 DOI: 10.1093/treephys/tpy095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/10/2018] [Accepted: 08/04/2018] [Indexed: 06/08/2023]
Abstract
The plant carbon balance depends on the coordination between photosynthesis and the long-distance transport of water and sugars. How plants modify the allocation to the different structures affecting this coordination under different environmental conditions has been poorly investigated. In this study, we evaluated the effect of soil water availability on the allocation to leaf, xylem and phloem structures in Fraxinus ornus L. We selected small individuals of F. ornus (height ~2 m) from sites contrasting in soil water availability (wet vs dry). We measured how the leaf (LM) and stem + branch biomass (SBM) are cumulated along the stem. Moreover, we assessed the axial variation in xylem (XA) and phloem tissue area (PA), and in lumen area of xylem vessels (CAxy) and phloem sieve elements (CAph). We found a higher ratio of LM:SBM in the trees growing under drier conditions. The long-distance transport tissues of xylem and phloem followed axial patterns with scaling exponents (b) independent of site conditions. PA scaled isometrically with XA (b ~ 1). While CAxy was only marginally higher at the wet sites, CAph was significantly higher at the drier sites. Our results showed that under reduced soil water availability, F. ornus trees allocate relatively more to the leaf biomass and produce more conductive phloem, which is likely to compensate for the drought-related hydraulic limitations to the leaf gas exchanges and the phloem sap viscosity.
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Affiliation(s)
- Natasa Kiorapostolou
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, Legnaro (PD), Italy
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, Legnaro (PD), Italy
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Salmon Y, Dietrich L, Sevanto S, Hölttä T, Dannoura M, Epron D. Drought impacts on tree phloem: from cell-level responses to ecological significance. Tree Physiol 2019; 39:173-191. [PMID: 30726983 DOI: 10.1093/treephys/tpy153] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/03/2018] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
On-going climate change is increasing the risk of drought stress across large areas worldwide. Such drought events decrease ecosystem productivity and have been increasingly linked to tree mortality. Understanding how trees respond to water shortage is key to predicting the future of ecosystem functions. Phloem is at the core of the tree functions, moving resources such as non-structural carbohydrates, nutrients, and defence and information molecules across the whole plant. Phloem function and ability to transport resources is tightly controlled by the balance of carbon and water fluxes within the tree. As such, drought is expected to impact phloem function by decreasing the amount of available water and new photoassimilates. Yet, the effect of drought on the phloem has received surprisingly little attention in the last decades. Here we review existing knowledge on drought impacts on phloem transport from loading and unloading processes at cellular level to possible effects on long-distance transport and consequences to ecosystems via ecophysiological feedbacks. We also point to new research frontiers that need to be explored to improve our understanding of phloem function under drought. In particular, we show how phloem transport is affected differently by increasing drought intensity, from no response to a slowdown, and explore how severe drought might actually disrupt the phloem transport enough to threaten tree survival. Because transport of resources affects other organisms interacting with the tree, we also review the ecological consequences of phloem response to drought and especially predatory, mutualistic and competitive relations. Finally, as phloem is the main path for carbon from sources to sink, we show how drought can affect biogeochemical cycles through changes in phloem transport. Overall, existing knowledge is consistent with the hypotheses that phloem response to drought matters for understanding tree and ecosystem function. However, future research on a large range of species and ecosystems is urgently needed to gain a comprehensive understanding of the question.
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Affiliation(s)
- Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, Gustaf Hällströmin katu 2b, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, Latokartanonkaari 7, University of Helsinki, Helsinki, Finland
| | - Lars Dietrich
- Department of Environmental Sciences, University of Basel, Schönbeinstrasse 6, Basel, Switzerland
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, PO Box 1663 MA 495, Los Alamos, NM, USA
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, Latokartanonkaari 7, University of Helsinki, Helsinki, Finland
| | - Masako Dannoura
- Kyoto University, Laboratory of Ecosystem Production and Dynamics, Graduate School of Global Environmental Studies, Kyoto, Japan
- Kyoto University, Laboratory of Forest Utilization, Graduate School of Agriculture, Kyoto, Japan
| | - Daniel Epron
- Université de Lorraine, AgroParisTech, INRA, UMR Silva, Faculté des Sciences et Technologies, Nancy, France
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Hubeau M, Mincke J, Vanhove C, Courtyn J, Vandenberghe S, Steppe K. Plant-PET to investigate phloem vulnerability to drought in Populus tremula under changing climate regimes. Tree Physiol 2019; 39:211-221. [PMID: 30597097 DOI: 10.1093/treephys/tpy131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 10/24/2018] [Accepted: 11/06/2018] [Indexed: 05/26/2023]
Abstract
Phloem transport is of great importance in trees to distribute assimilated carbon across the entire tree. Nevertheless, knowledge of phloem is incomplete, because of the complexity of measuring its transport and characteristics. Only few studies have addressed how phloem transport might alter under climatic changes, with most data originating from theoretical studies. We measured phloem characteristics in leaves of young Populus tremula L. trees grown during 5 months under ambient (TA, 404 ppm ± 5) and elevated (TE, 659 ppm ± 3) atmospheric CO2 concentration ([CO2]) using a combination of positron emission tomography (PET) and compartmental modelling. Short-term phloem dynamics were measured in vivo and non-invasively using the short-lived isotope of carbon, 11C (half-life 20.4 min). Trees were scanned in well-watered and dry conditions to assess changes in phloem characteristics induced by drought. Reliability of the PET-derived results was verified with reported observations in the literature. Phloem speed was highest in well-watered TE trees and strongly reduced by 81% under drought, whereas phloem speed reduced by 61% in TA trees at the same level of drought. These findings led us to speculate that phloem transport in TE trees might be more vulnerable to drought. We discuss how a higher phloem vulnerability to drought in a changing climate could impact tree hydraulic functioning. Taken together our results suggest that trees grown for 5 months under elevated [CO2] seem to be less well-acclimated to face projected hotter droughts in a changing climate.
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Affiliation(s)
- Michiel Hubeau
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Jens Mincke
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Medical Imaging and Signal Processing - Innovative Flemish In-vivo Imaging Technology, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium
| | - Christian Vanhove
- Medical Imaging and Signal Processing - Innovative Flemish In-vivo Imaging Technology, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium
| | - Jan Courtyn
- Medical Molecular Imaging and Therapy, Department of Radiology and Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Stefaan Vandenberghe
- Medical Imaging and Signal Processing - Innovative Flemish In-vivo Imaging Technology, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Liu H, Gleason SM, Hao G, Hua L, He P, Goldstein G, Ye Q. Hydraulic traits are coordinated with maximum plant height at the global scale. Sci Adv 2019; 5:eaav1332. [PMID: 30788435 PMCID: PMC6374111 DOI: 10.1126/sciadv.aav1332] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 01/04/2019] [Indexed: 05/17/2023]
Abstract
Water must be transported long distances in tall plants, resulting in increasing hydraulic resistance, which may place limitations on the maximum plant height (H max) in a given habitat. However, the coordination of hydraulic traits with H max and habitat aridity remains poorly understood. To explore whether H max modifies the trade-off between hydraulic efficiency and safety or how water availability might influence the relationship between H max and other hydraulic traits, we compiled a dataset including H max and 11 hydraulic traits for 1281 woody species from 369 sites worldwide. We found that taller species from wet habitats exhibited greater xylem efficiency and lower hydraulic safety, wider conduits, lower conduit density, and lower sapwood density, which were all associated with habitat water availability. Plant height and hydraulic functioning appear to represent a single, coordinated axis of variation, aligned primarily with water availability, thus suggesting an important role for this axis in species sorting processes.
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Affiliation(s)
- Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
| | - Sean M. Gleason
- Water Management and Systems Research Unit, USDA-ARS, Fort Collins, CO 80526, USA
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110010, China
| | - Lei Hua
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Guillermo Goldstein
- Department of Biology, University of Miami, PO Box 249118, Coral Gables, FL 33124, USA
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Nuñez, Buenos Aires C1428EGA, Argentina
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- Corresponding author.
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32
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Dobbelstein E, Fink D, Öner-Sieben S, Czempik L, Lohaus G. Seasonal changes of sucrose transporter expression and sugar partitioning in common European tree species. Tree Physiol 2019; 39:284-299. [PMID: 30388274 DOI: 10.1093/treephys/tpy120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 09/17/2018] [Accepted: 10/04/2018] [Indexed: 05/13/2023]
Abstract
In temperate woody species, carbon transport from source to sink tissues is a striking physiological process, particularly considering seasonal changes. The functions of different tissues can also alternate across the seasons. In this regard, phloem loading and sugar distribution are important aspects of carbon partitioning, and sucrose uptake transporters (SUTs) play a key role in these processes. Therefore, the influence of seasons and different light-dark conditions on the expression of SUTs from 3-year-old Fagus sylvatica L., Quercus robur L. and Picea abies (L.) Karst. trees were analyzed. In addition, tissue-specific sugar and starch contents under these different environmental conditions were determined. Putative SUTs were identified in the gymnosperms (Picea abies, Ginkgo biloba L.), here for the first time, and also in the angiosperms (Q. robur, F. sylvatica). The identified SUT sequences of the different tree species cluster into three types, similar to other SUTs from herbaceous and tree species. Furthermore, the sequences from angiosperm and those from gymnosperm species form distinct clusters within the three types of SUTs. In F. sylvatica, Q. robur and P. abies, the expression levels of the different SUTs during seasons showed marked variations. Because of the high expression levels of type I SUTs in bark, wood and leaves during active growing phases in spring and summer, it can be assumed that they are involved in phloem loading, sucrose retrieval and possibly in further physiological processes. The expression patterns also indicate a flexible expression in all tissues depending on physiological requirements and environmental conditions. Compared with type I SUTs, the seasonal variations of type II SUT expression were less pronounced, whereas the seasonal variations of the type III SUT expression patterns were partly reverse. In addition to the seasonal regulation, the expressions of the different SUTs were also regulated by light in a diurnal manner.
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Affiliation(s)
- Elena Dobbelstein
- Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Gaußstr. 20, Wuppertal, Germany
| | - Daniel Fink
- Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Gaußstr. 20, Wuppertal, Germany
| | - Soner Öner-Sieben
- Clinic for General Pediatrics, Neonatology and Paediatric Cardiology, University Clinic Düsseldorf, Moorenstr. 5, Düsseldorf, Germany
| | - Laura Czempik
- Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Gaußstr. 20, Wuppertal, Germany
| | - Gertrud Lohaus
- Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Gaußstr. 20, Wuppertal, Germany
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Losada JM, Holbrook NM. Scaling of phloem hydraulic resistance in stems and leaves of the understory angiosperm shrub Illicium parviflorum. Am J Bot 2019; 106:244-259. [PMID: 30793276 DOI: 10.1002/ajb2.1241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY Recent studies in canopy-dominant trees revealed axial scaling of phloem structure. However, whether this pattern is found in woody plants of the understory, the environment of most angiosperms from the ANA grade (Amborellales-Nymphaeales-Austrobaileyales), is unknown. METHODS We used seedlings and adult plants of the understory tropical shrub Illicium parviflorum, a member of the lineage Austrobaileyales, to explore the anatomy and physiology of the phloem in their aerial parts, including changes through ontogeny. KEY RESULTS Adult plants maintain a similar proportion of phloem tissue across stem diameters, but larger conduit dimensions and number cause the hydraulic resistance of the phloem to decrease toward the base of the plant. Small sieve plate pores resulted in an overall higher sieve tube hydraulic resistance than has been reported in other woody angiosperms. Sieve elements increase in size from minor to major leaf veins, but were shorter and narrower in petioles. The low carbon assimilation rates of seedlings and mature plants contrasted with a 3-fold higher phloem sap velocity in seedlings, suggesting that phloem transport velocity is modulated through ontogeny. CONCLUSIONS The overall architecture of the phloem tissue in this understory angiosperm shrub scales in a manner consistent with taller trees that make up the forest canopy. Thus, the evolution of larger sieve plate pores in canopy-dominant trees may have played a key role in allowing woody angiosperms to extend beyond their understory origins.
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Affiliation(s)
- Juan M Losada
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
- Arnold Arboretum of Harvard University, 1300 Centre St., Boston, MA, 02130, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
- Arnold Arboretum of Harvard University, 1300 Centre St., Boston, MA, 02130, USA
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Kalmbach L, Helariutta Y. Sieve Plate Pores in the Phloem and the Unknowns of Their Formation. Plants (Basel) 2019; 8:E25. [PMID: 30678196 PMCID: PMC6409547 DOI: 10.3390/plants8020025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/17/2019] [Accepted: 01/19/2019] [Indexed: 01/13/2023]
Abstract
Sieve pores of the sieve plates connect neighboring sieve elements to form the conducting sieve tubes of the phloem. Sieve pores are critical for phloem function. From the 1950s onwards, when electron microscopes became increasingly available, the study of their formation had been a pillar of phloem research. More recent work on sieve elements instead has largely focused on sieve tube hydraulics, phylogeny, and eco-physiology. Additionally, advanced molecular and genetic tools available for the model species Arabidopsis thaliana helped decipher several key regulatory mechanisms of early phloem development. Yet, the downstream differentiation processes which form the conductive sieve tube are still largely unknown, and our understanding of sieve pore formation has only moderately progressed. Here, we summarize our current knowledge on sieve pore formation and present relevant recent advances in related fields such as sieve element evolution, physiology, and plasmodesmata formation.
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Affiliation(s)
- Lothar Kalmbach
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.
| | - Ykä Helariutta
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
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Liesche J, Schulz A. Phloem transport in gymnosperms: a question of pressure and resistance. Curr Opin Plant Biol 2018; 43:36-42. [PMID: 29304388 DOI: 10.1016/j.pbi.2017.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 06/07/2023]
Abstract
Even in the highest trees, carbon is efficiently distributed from leaves to heterotrophic tissues like fruit, flowers and roots. This long-distance transport happens in the highly specialized sieve elements of the phloem. In gymnosperms, sieve element anatomy appears to be less suited for mass flow of phloem sap than that of angiosperms. This review covers available data on gymnosperm phloem to evaluate if it functions differently from that of angiosperms. Although current evidence suggests that, despite a higher pathway resistance, a single source-to-sink turgor pressure gradient can drive mass flow, several questions remain unanswered. These include how endoplasmic reticulum-complexes in sieve elements influence flow, as well as what the effect of symplasmic coupling along the whole phloem pathway could be.
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Affiliation(s)
- Johannes Liesche
- College of Life Science, Department of Biology, Northwest A&F University, 3 Taicheng Road, 712100 Yangling, Shaanxi, China
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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Holbrook NM, Knoblauch M. Editorial overview: Physiology and metabolism: Phloem: a supracellular highway for the transport of sugars, signals, and pathogens. Curr Opin Plant Biol 2018; 43:iii-vii. [PMID: 29853282 DOI: 10.1016/j.pbi.2018.05.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA.
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Rockwell FE, Gersony JT, Holbrook NM. Where does Münch flow begin? Sucrose transport in the pre-phloem path. Curr Opin Plant Biol 2018; 43:101-107. [PMID: 29704829 DOI: 10.1016/j.pbi.2018.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/30/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Current conceptions of sucrose export largely neglect the effect of transpiration-induced water potential gradients within leaf mesophyll, even as the mix of convection and diffusion in the pre-phloem path remains uncertain. It is also generally held that the relative importance of convection and diffusion in the pre-phloem path is controlled by the ratio of their respective mass transfer coefficients. Here, we consider pre-phloem sucrose transport in the presence of adverse water potential gradients, finding that whether convection impedes or aids sucrose delivery to the phloem is independent of the permeability of the plasmodesmata to bulk flow, and depends only on assimilation rate, path-length, and the diffusivity. For most tissues subject to transpiration, convection through plasmodesmata pushes sugar away from the phloem.
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Affiliation(s)
- Fulton E Rockwell
- Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Jessica T Gersony
- Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA 02138, USA
| | - N Michele Holbrook
- Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA 02138, USA.
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Carvalho MR, Losada JM, Niklas KJ. Phloem networks in leaves. Curr Opin Plant Biol 2018; 43:29-35. [PMID: 29306742 DOI: 10.1016/j.pbi.2017.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/04/2017] [Accepted: 12/16/2017] [Indexed: 06/07/2023]
Abstract
The survival of all vascular plants depends on phloem and xylem, which comprise a hydraulically coupled tissue system that transports photosynthates, water, and a variety of other molecules and ions. Although xylem hydraulics has been extensively studied, until recently, comparatively little is known quantitatively about the phloem hydraulic network and how it is functionally coupled to the xylem network, particularly in photosynthetic leaves. Here, we summarize recent advances in quantifying phloem hydraulics in fully expanded mature leaves with different vascular architectures and show that (1) the size of phloem conducting cells across phylogenetically different taxa scales isometrically with respect to xylem conducting cell size, (2) cell transport areas and lengths increase along phloem transport pathways in a manner that can be used to model Münch's pressure-flow hypothesis, and (3) report observations that invalidate da Vinci's and Murray's hydraulic models as plausible constructs for understanding photosynthate transport in the leaf lamina.
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Affiliation(s)
- Mónica R Carvalho
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA; Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Panama
| | - Juan M Losada
- Arnold Arboretum, Harvard University, 1300 Centre St., Boston, MA 02131, USA
| | - Karl J Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
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Ryan MG, Robert EMR. Zero-calorie sugar delivery to roots. Nat Plants 2017; 3:922-923. [PMID: 29209079 DOI: 10.1038/s41477-017-0070-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Michael G Ryan
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, USA.
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